Improvement in augebs



Will

guitar tetra iatmt ffin'r.

JOHN A. McGEE,-OF NEWYORK, N."Y., ASSIGNOR TO THEODORE MACE,

OF SAME PLACE. 3

Letters PatentNo. 72,065, dated December 10, 1867.

IMPROVEMENT IN AUGERS.

TO ALL WHOM IT MAY CONCERN:

Be it known that I, JOHN A.-McGEE, of the city and State of New York,have invented and made a certain new and useful Improvement inBoring-Instruments; and I do hereby declare the following to be a full,clear, and exact description of the said invention, reference being hadto the annexed drawing, making part of this specification, wherein-Figure 1 is a side view of an anger formed with my improvedcutting-edge.

Figure 2 is a view endwise of the said auger; and

Figure 3 is an elevation at right angles to fig. 1.

Similar marks of reference denote the same parts.

Boring-tools have heretofore been made, in which the cutting-edges havebeen made of two parts, the one acting to form a circular incision, theother to clear out the wood. In'augers of this kind a difliculty isexperienced in sharpening the cutting-edge, particularly in smallangers. Augers' have also been made with the cutting-edge curved upwardsor towards the handle, but with these the cutting of each shaving of thewood extends entirely across the cutting-edge, and the shaving at theouter edge is very thin, in consequence of the convergence of the arcsdescribed by the cutting-edge, the same as in a pod-auger, and after thescrew-point has passed through the wood, and no longer draws the'augeralong with regularity, there is a' difiiculty in finishing the hole witha smooth cut..

The nature of my said invention consists in a boring toohin which thecutting-edge is extended outwardly from the base of the tapering screw,and curved backward and downward until it intersects the periphery ofthe itool; thereby a circular incision is first made by the revolutionof the tool, and then a'shaving is removed by the hither parts of thesame cutting-edge. This character of cutting-edge is sharpened almostentirely by filing'upon jthe lower surface, where there is easy access;hence the tool is kept in order with facility..

In the drawing, a represents a portion ofthe twist of the auger, b theconical screw-point. The cuttingledges 2' are formed nearly straight,and as tangents to the base of the screw 6, as atl; thence thecutting-edges are formed as compound curves, at 2, slanting backwards,so as to separate the grain of the wood by a shearing cut, and curvingdownwards, or towards the screw-point, so as to separate the wood by acircular incision, in gadvance of the part 1 of said edge which removesthe wood. i The cutting-edge in my said tool being a. compound curvebackwards and downwards, is a shearing out lthroughout its entirelength. The shaving that is removed is curled in the act of being cut,so as to easily free iitself as the screw portion of the bit passes italong. The bit can be filed and sharpened with ease; and the lastiportion of the wood removed, when the hole is bored through, is in theform of a. disk around the screw-point, iand the cut is free andsmooththrough its entire length. i

What I-claim, and desire to secure by Letters Patent, is Theboring-instrument formed with a cutting-edge extending outwardly fromthe base of the tapering screw, land curved backwards and downwardsuntil it intersects the periphery of the tool, as and for the purposesiset forth. a In witness whercofl'I havehereunto set my signature, this20th day of June, A. D; 1867.

- Y JOHN A. McGEE.

Witnesses: Gno. D. WALKER, l Giro. T. PINCKNEY.

